Computer systems are increasingly being configured to accept inputs from natural user interfaces (NUIs) that allow users to interact with a computer system via natural, intuitive motions. For example, a computing system may be configured to accept user inputs in the form of user motions detected by a camera, such as a depth-sensing camera. Images from the camera are analyzed to locate people in the images, and to track motions of those people over time. Filters may then be used to determine whether a detected motion is a recognized user input.